DESCRIPTION: (Applicant's Abstract) A dual diagnosis of posttraumatic stress disorder (PTSD) and substance use disorder (SUD) is relatively common and is associated with a poor prognostic outcome. Treatment for comorbid PTSD and SUD is of particular relevance for incarcerated women whose rates of PTSD and SUD are considerably higher compared to women in the general population. Yet virtually no treatments have been developed or systematically evaluated which target concurrently the symptoms of PTSD and SUD in this underserved population. One goal of this Stage I treatment development grant is to expand an existing treatment, "Seeking Safety: A Cognitive-Behavioral Psychotherapy Treatment for PTSD and SUD" (SS) to meet the specific needs of incarcerated women with these co-existing disorders. SS treatment targets deficits common to both PTSD and SUD, and is one of the few treatments for comorbid PTSD and SUD with efficacy data. Another goal of this project is to collect preliminary data on the efficacy of an expanded SS treatment for our target population. Our specific aims are: 1) Expand SS group treatment to include postrelease, individual sessions. 2) Expand the existing SS treatment manual to include these individual sessions. 3) Implement a therapist training program. 4) Expand existing competence and adherence rating scales for SS treatment to include adherence and competence items for the expanded version of SS treatment and test the psychometric properties of these items. 5) Conduct a randomized controlled pilot study to evaluate the initial efficacy, feasibility, and acceptability of the proposed expanded SS treatment compared to a reference condition ("treatment as usual") in a sample of 40 incarcerated women with comorbid PTSD and SUD. Primary treatment outcomes will be: a) number of substance use days, b) degree of PTSD symptoms, and c) severity of legal problems.